First nitrogen-seeding experiments in JET with the ITER-like Wall

In this contribution we present results from the first N-2 seeding experiments in JET performed after installation of the ITER-like Wall. Gas balance measurements for seeded L-mode discharges indicate very strong N-2 retention as well as a potential increase in D-2 retention. The possible influence of ammonia production on this apparent retention is discussed. Plasma parameters and impurity content were monitored throughout the seeded discharges as well as during subsequent clean-up discharges. These experiments give first insight into phenomena related to the use of nitrogen as seeding gas in JET with the ITER-like Wall, such as ammonia production and nitrogen legacy. (C) 2013 Elsevier B. V. All rights reserved.